Display device

ABSTRACT

Provided is a display device, comprising a display panel which comprises a first area and a second area located around the first area; and an under-panel sheet which is located under the display panel and overlaps the first area and the second area, wherein the under-panel sheet comprises a buffer member and a strength reinforcing member, wherein the strength reinforcing member is thinner than the buffer member, and a ratio of a thickness of the buffer member to a thickness of the strength reinforcing member is 3 to 6 times.

This application is a continuation application of U.S. patentapplication Ser. No. 16/505,671 filed on Jul. 8, 2019, which is acontinuation application of U.S. patent application Ser. No. 15/867,247filed on Jan. 10, 2018 (now U.S. Pat. No. 10,374,191), claims thebenefit of Korean Patent Application No. 10-2017-0084440, filed on Jul.3, 2017, in the Korean Intellectual Property Office, the disclosure ofwhich is incorporated herein by reference in its entirety.

BACKGROUND 1. Field

The present inventive concept relates to a display device.

2. Description of the Related Art

Organic light emitting displays have excellent luminance, drivingvoltage and response speed characteristics and can be multi-colored. Dueto these advantages, the organic light emitting displays are beingapplied to various products, mainly smartphones. An organic lightemitting display includes a display panel including an organic lightemitting element. In the organic light emitting element, a cathode andan anode are arranged around an organic light emitting layer. When avoltage is applied to both electrodes, visible light is generated fromthe organic light emitting layer connected to the electrodes.

Organic light emitting displays are widely used in portable electronicdevices such as smartphones, and are easily exposed to external impact.Further, since an organic light emitting layer is vulnerable tomoisture, an organic light emitting display can be damaged by a liquidintroduced from the outside. To protect against such dangers, thedisplay device includes functional members having functions such asbuffer and waterproof functions.

SUMMARY

Aspects of the inventive concept provide a display device having anenhanced strength reinforcing function.

Aspects of the inventive concept also provide a display device having anenhanced waterproof function.

However, aspects of the inventive concept are not restricted to the oneset forth herein. The above and other aspects of the inventive conceptwill become more apparent to one of ordinary skill in the art to whichthe inventive concept pertains by referencing the detailed descriptionof the inventive concept given below.

According to an aspect of the inventive concept, there is provided adisplay device comprising a display panel which comprises a first areaand a second area located around the first area; and an under-panelsheet which is located under the display panel and overlaps the firstarea and the second area, wherein the under-panel sheet comprises abuffer member and a strength reinforcing member, wherein the strengthreinforcing member is thinner than the buffer member, and a ratio of athickness of the buffer member to a thickness of the strengthreinforcing member is about 3 to about 6 times.

According to another aspect of the inventive concept, there is provideda display device comprising a display panel which comprises a first areaand a second area located around the first area, a window which isdisposed on the display panel and comprises a third area overlapping thedisplay panel and a fourth area protruding outward from the displaypanel, an under-panel sheet which is disposed under the display paneland overlaps the first area and the second area, and a waterproof memberwhich is disposed around the under-panel sheet, wherein the waterproofmember comprises a plurality of line-shaped waterproof tapes extendingalong sides of the under-panel sheet and a plurality of waterproofresins, each disposed in a space between the waterproof tapes.

According to another aspect of the inventive concept, there is provideda display device comprising a display panel, a window which is disposedon the display panel and comprises a first area overlapping the displaypanel and a second area protruding outward from the display panel, anunder-panel sheet which is disposed under the display panel and overlapsthe display panel, and a waterproof member which is disposed on thesecond area of the window and does not overlap the under-panel sheet.

Any of the aspects of the inventive concept may additionally have thedisplay device wherein the first area is generally located in a plane,and the second area is located in a plane different from the plane.

The display device may have wherein the strength reinforcing membercomprises polyimide (PI) or polyethylene terephthalate (PET).

The display device may have wherein the thickness of the strengthreinforcing member is about 25 to about 50 μm.

The display device may have wherein the thickness of the buffer memberis about 100 to about 150 μm

The display device may further comprise a first adhesive member which isdisposed between the strength reinforcing member and the buffer member.

The display device may have wherein a thickness of the first adhesivemember is about 20 to about 50 μm.

The display device may have wherein a ratio of the thickness of thestrength reinforcing member to the thickness of the first adhesivemember is about 1 to about 1.04 times.

The display device may have wherein the under-panel sheet furthercomprises a heat dissipation member.

The display device may further comprise a second adhesive member whichis disposed between the heat dissipation member and the strengthreinforcing member.

The display device may have wherein the second adhesive member comprisesa thermosetting epoxy or acrylic material.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readilyappreciated from the following description of the embodiments, taken inconjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a display device according to anembodiment;

FIG. 2 is an exploded perspective view of the display device accordingto the embodiment of FIG. 1;

FIG. 3 is a bottom view of the display device according to theembodiment of FIG. 1;

FIG. 4 is a cross-sectional view taken along the line IV-IV′ of FIG. 3;

FIG. 5 is a cross-sectional view taken along the line V-V′ of FIG. 3;

FIG. 6 is a cross-sectional view taken along the VI-VI′ of FIG. 3;

FIG. 7 is a cross-sectional view of an under-panel sheet according to anembodiment;

FIG. 8 is a cross-sectional view of an under-panel sheet according to anembodiment;

FIG. 9 is an exploded perspective view of a display device according toan embodiment;

FIG. 10 is a rear view of the display device according to the embodimentof FIG. 9;

FIG. 11 is a cross-sectional view taken along the line XI-XI′ of FIG.10;

FIG. 12 is a cross-sectional view taken along the line XII-XII′ of FIG.10; and

FIG. 13 is a rear view of a display device according to an embodiment.

DETAILED DESCRIPTION

Advantages and features of the present disclosure and methods ofaccomplishing the same may be understood more readily by reference tothe following detailed description of exemplary embodiments and theaccompanying drawings. The present disclosure may, however, be embodiedin many different forms and should not be construed as being limited tothe exemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the concept of the present disclosure tothose skilled in the art, and the present disclosure will only bedefined within the scope of the appended claims.

Cases where elements or layers are referred to as being located “on”other elements or layers include all the cases where other layers orother elements are interposed directly on or between other elements.Meanwhile, cases where the elements are “directly on” indicate that noother element or layer is interposed therebetween. Same referencenumerals refer to the same constituent elements throughout thespecification. Term ‘and/or” includes each and every combination of oneor more of the referenced items.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another element. Thus, a first element discussed belowcould be termed a second element without departing from the teachings ofthe present inventive concept.

Hereinafter, embodiments of the inventive concept will be described withreference to the attached drawings. FIG. 1 is a perspective view of adisplay device 10 according to an embodiment. FIG. 2 is an explodedperspective view of the display device 10 according to the embodiment ofFIG. 1.

In FIG. 1, a portable terminal is illustrated as an example to which thedisplay device 10 according to the embodiment is applied. The portableterminal may be a tablet PC, a smartphone, a personal digital assistant(PDA), a wearable electronic device, or the like. However, the displaydevice 10 according to the embodiment is not necessarily applied to theabove examples and can also be applied to large electronic devices suchas a television and an external billboard as well as to small and mediumelectronic devices such as a personal computer, a notebook computer, acar navigation unit and a camera. That is, the display device 10according to the embodiment can be applied to other electronic deviceswithout departing from the spirit of the inventive concept.

Referring to FIGS. 1 and 2, the display device 10 includes a displaypanel 100, an under-panel sheet 400 disposed under the display panel100, a waterproof member 500 disposed around the under-panel sheet 400,and a bracket 60 disposed under the waterproof member 500. The displaydevice 10 may further include a window 200 disposed on the display panel100. Unless otherwise defined, the terms “on” and “upper surface” usedherein denote a display surface side of the display panel 1, and theterms “under” and “lower surface” used herein denote an opposite side ofthe display panel 100 from the display surface side.

The display device 10 is divided into a display area DA and anon-display area NDA. The display area DA is an area where a screen isdisplayed, and the non-display area NDA is an area where a screen is notdisplayed. The non-display area NDA is disposed around the display areaDA. For example, when the display area DA is rectangular, thenon-display area NDA may be disposed along four sides of the displayarea DA.

The display device 10 may be rectangular in plan view. The displaydevice 10 may include a first long side LS1 and a second long side LS2facing each other and a first short side SS1 and a second short side SS2facing each other. Each corner where the long side LS1 or LS2 of thedisplay device 10 meets the short side SS1 or SS2 of the display device10 may be a right angle, but can also form a curved surface asillustrated in FIG. 1. The planar shape of the display device 10 is notlimited to the above example and can also be a circular shape or othershapes.

The display panel 100 is a panel for displaying a screen. For example,the display panel 100 may be an organic light emitting display panel. Inthe following embodiment, a case where an organic light emitting displaypanel is applied as the display panel 100 will be described. However,other types of display panels such as an electrophoresis device can alsobe applied as the display panel 100.

The display panel 100 includes a plurality of organic light emittingelements disposed on a substrate. The substrate may be a rigid substratemade of, e.g., glass or a flexible substrate made of, e.g., polyimide.When a polyimide substrate is used as the substrate, the organic lightemitting display panel 100 can be curved, bent, folded or rolled.

The window 200 is disposed on the display panel 100. The window 200 isdisposed on the display panel 100 to protect the display panel 100 fromexternal impact while transmitting light emitted from the display panel100. The window 200 may be made of a transparent material such as glassor resin.

The window 200 may overlap the display panel 100 and cover the entiresurface of the display panel 100. The window 200 may be larger than thedisplay panel 100. For example, the window 200 may protrude furtheroutward than the display panel 100 at both short sides SS1 and SS2 ofthe display device 10.

In an embodiment, a touch panel 300 may be disposed between the displaypanel 100 and the window 200. The touch panel 300 may have substantiallythe same size as the display panel 100 and may overlap the display panel100. The display panel 100 and the touch panel 300 may be bonded by anoptically clear adhesive (OCA) or an optically clear resin (OCR), andthe touch panel 300 and the window 200 may be bonded by the OCA or theOCR. The touch panel 300 can be omitted. In this case, the display panel100 and the window 200 may be bonded by the OCA or the OCR. In someembodiments, the display panel 100 may further include a touch electrodeunit.

The under-panel sheet 400 is disposed under the display panel 100. Theunder-panel sheet 400 may have substantially the same size as thedisplay panel 100 and may overlap the display panel 100. The under-panelsheet 400 is attached to a lower surface of the display panel 100 toperform a buffering function for protecting the display panel 100 fromexternal impact and a heat dissipation function for releasing heatgenerated from the display panel 100 to the outside. The under-panelsheet 400 may further perform an electromagnetic wave shieldingfunction, a grounding function, a strength enhancing function, and/or adigitizing function.

The waterproof member 500 is disposed along each side of the under-panelsheet 400. The waterproof member 500 may overlap the under-panel sheet400 or may be separated from the under-panel sheet 400 by apredetermined distance to not overlap the under-panel sheet 400. Thewaterproof member 500 can prevent water and other liquids frompenetrating into the display device 10. The under-panel sheet 400 andthe waterproof member 500 will be described in detail later.

The bracket 600 is disposed under the waterproof member 500. The bracket600 is disposed under the waterproof member 500 to protect the internalcomponents of the display device 10 disposed on the waterproof member500 from the outside. The bracket 600 may be shaped like a quadrilateralbox having a receiving area. That is, the bracket 600 includes four sidesurfaces and a bottom surface, and the display panel 100, the touchpanel 300, the under-panel sheet 400 and the waterproof member 5 may bedisposed in an internal space formed by the side surfaces and bottomsurface of the bracket 600.

In an embodiment, the bracket 600 may be tightly coupled to thewaterproof member 500 without a gap in order to prevent liquids such asmoisture from penetrating into the display device 10. In addition, aportion of the bracket 600 may be exposed to form the external design ofthe display device 10.

The display device 10 may include a first area CA and a second area EAdisposed around the first area CA. Specifically, the first area CA maybe disposed substantially on one plan, and the second area EA is not onthe same plane as the first area CA. In an embodiment, the second areaEA of the display device 10 may have a bent shape. For example, thesecond area EA may be bent or curved downward from the plane where thefirst area CA is located. The second area EA may include a surfaceconvexly curved in an outward direction. Alternatively, the second areaEA may have a flat surface but may be located in a plane at apredetermined angle to the plane of the first area CA.

In an embodiment, the display device 10 may be composed only of thefirst area CA. That is, the display device 10 may include only a flatportion located substantially in one plane.

In an embodiment, the display device 10 may not be divided into thefirst area CA and the second area EA. Instead, the display device 10 maybe composed of a single continuous curved surface. For example, thedisplay device 10 may be shaped like a dome.

For ease of description, the following description will be based on thedisplay device 10 including the first area CA and the second area EAlocated in a different plane from the first area CA, and display devices20 and 30 composed only of the first area CA will be described later.

The second area EA may be located on both long sides LS1 and LS2 of therectangular display device 10 or only on any one of the first long sideLS1 and the second long side LS2. Although not illustrated in thedrawings, the second area EA can also be disposed on either one or bothof the short sides SS1 and SS2 of the display device 10.

The display panel 100, the touch panel 300, the window 200, theunder-panel sheet 400, the waterproof member 500, and the bracket 600may all be located in the first area CA and the second area EA.

The under-panel sheet 400 and the waterproof member 500 described abovewill now be described in more detail.

FIG. 3 is a bottom view of the display device 10 according to theembodiment of FIG. 1. FIG. 4 is a cross-sectional view taken along theline IV-IV′ of FIG. 3. FIG. 5 is across-sectional view taken along theline V-V′ of FIG. 3. FIG. 6 is a cross-sectional view taken along theVI-VI′ of FIG. 3.

Referring to FIGS. 2 through 6, the under-panel sheet 400 includes atleast one functional layer. The functional layer may be a layer thatperforms a heat dissipation function, an electromagnetic wave shieldingfunction, a grounding function, a buffering function, a strengthenhancing function, a support function, and/or a digitizing function.The functional layer may be a sheet layer made of a sheet or a filmlayer made of a film. However, the functional layer is not limited tothe sheet layer or the film layer and can also be a thin layer, acoating layer, a panel, a plate, or the like.

The under-panel sheet 400 may include a plurality of functional layersand an interlayer bonding layer for bonding the functional layerstogether. The functional layers may overlap each other. Adjacentfunctional layers may be bonded together by the interlayer bondinglayer. Each functional layer and the interlayer bonding layer may havethe same size in plan view. However, the inventive concept is notlimited to this case, and some or all of the functional layers and theinterlayer bonding layer can have different sizes. In addition, any oneof the functional layers and the interlayer bonding layer may protrudefurther outward in a specific direction or in all directions than theother layers. The planar shape of the under-panel sheet 400 may bedefined by connecting maximum protruding portions of the stackedfunctional layers and interlayer bonding layer. The specific compositionof the functional layers and interlayer bonding layer will be describedlater.

As described above, the under-panel sheet 400 may have substantially thesame size as the display panel 100 and may overlap the display panel100. That is, the under-panel sheet 400 may be attached to the lowersurface of the display panel 100 by an adhesive member (notillustrated). Specifically, the under-panel sheet 400 may be bent in thesame shape as the display panel 100 in the second area EA of the displaydevice 10, that is, at both long sides LS1 and LS2 of the display device10. In other words, the under-panel sheet 400 having a flat shape may bebent along the curvature of the second area EA of the display panel 100as it is attached to the lower surface of the display panel 100 havingthe second area EA. As a result, the under-panel sheet 400 can beattached to the lower surface of the display panel 100 without a liftedarea, and the curvature of the second area EA of the display panel 100may be directly proportional to the curvature of the second area EA ofthe under-panel sheet 400.

A side surface of the under-panel sheet 400 may be substantially alignedwith a side surface of the display panel 100. When the side surface ofthe under-panel sheet 400 is substantially aligned with the side surfaceof the display panel 100, an extension surface of the side surface ofthe under-panel sheet 400 may not only pass the side surface of thedisplay panel 100, but the side surface of the under-panel sheet 400 mayalso be located further in than the side surface of the display panel100 by a distance that is hard to be recognized with the naked eye. Inan embodiment, as illustrated in FIG. 4, a first side surface 400S1 ofthe under-panel sheet 400 may be located further in than a first sidesurface 100S1 of the display panel 100 at both long sides LS1 and LS2 ofthe display device 10, that is, in the second area EA of the displaydevice 10. However, the distance between the first side surface 400S1 ofthe under-panel sheet 400 and the first side surface 100S1 of thedisplay panel 100 may be very small. Alternatively, as illustrated inFIG. 6, an extension line of a second side surface 400S2 of theunder-panel sheet 400 may pass a second side surface 100S2 of thedisplay panel 100. When it is necessary to distinguish each side surfacein the present specification and the accompanying drawings, the sidesurfaces will be referred as a “first side surface S1,” a “second sidesurface S2.” a “third side surface S3,” and a “fourth side surface S2.”However, when a side surface is simply mentioned without need todistinguish between the different side surfaces, it will be referred asa “side surface.” In addition, the first side surface S1 denotes a sidesurface corresponding to the first long side LS1 of the display device10, and the second side surface S2, the third side surface S3, and thefourth side surface S4 are arranged in a clockwise direction from thefirst side surface S1.

In an embodiment, a flexible printed circuit board (FPCB) 110 may bedisposed on a side of the display panel 100. In this case, a sidesurface of the under-panel sheet 400 may be located further in than aside surface of the display panel 100. That is, as illustrated in FIG.5, when the FPCB 110 is disposed on the second short side SS2 of thedisplay device 10, a fourth side surface 400S4 of the under-panel sheet400 may be located further in than a fourth side surface 10054 of thedisplay panel 100 by a predetermined distance. In other words, thedisplay panel may include an area protruding outward from the fourthside surface 400S4 of the under-panel sheet 400 to be exposed. The lowersurface of the display panel 100 exposed by the under-panel sheet 400may provide a space in which the FPCB 110 can be disposed.

Referring again to FIGS. 2 and 3, the waterproof member 500 may bedisposed around the under-panel sheet 400. The waterproof member 500 mayinclude, but not limited to, a plurality of line-shaped waterproof tapes510 extending along the sides of the under-panel sheet 400 and aplurality of waterproof resins 520, each disposed in a space between thewaterproof tapes 510. Although not illustrated in the drawings, thewaterproof tapes 510 can forma continuous quadrilateral frame shape. Inthis case, the waterproof resins 520 may be omitted.

In an embodiment, the waterproof tapes 510 may be disposed along thesides LS1, LS2, SS1 and SS2 of the display device 10. Specifically, afirst waterproof tape 511, a second waterproof tape 512, a thirdwaterproof tape 513, and a fourth waterproof tape 514 may be disposedalong both long sides LS1 and LS2 and both short sides SS1 and SS2 ofthe display device 10. The planar shape of each of the waterproof tapes510 may be substantially similar to a rectangle. However, each of thewaterproof tapes 510 may include a hole or a protruding regioncorresponding to a camera region, a speaker region, and the like.

The waterproof tapes 510 may be attached to a lower surface of theunder-panel sheet 400 on both long sides LS1 and LS2 of the displaydevice 10. Specifically, the first waterproof tape 511 and the thirdwaterproof tape 513 may have the same shape as the planar shape of theunder-panel sheet 400 and may overlap the under-panel sheet 400.Referring to FIG. 4, an outer side surface 511OS of the first waterprooftape 511 may be substantially aligned with the first side surface 400S1of the under-panel sheet 400, and an inner side surface 511IS of thefirst waterproof tape 511 may be substantially aligned with a boundarybetween the second area EA and the first area CA. That is, the firstwaterproof tape 511 and the third waterproof tape 513 may be disposedonly in the second area EA on both long sides LS1 and LS2 of the displaydevice 10. However, the inventive concept is not limited to this case,and the first waterproof tape 511 and the third waterproof tape 513 canalso extend from the second area EA to the first area CA.

The waterproof tapes 510 may not overlap the display panel 100 on bothshort sides SS1 and SS2 of the display device 10 and may be attached toa lower surface of the window 200. Specifically, each of the secondwaterproof tape 512 and the fourth waterproof tape 514 may be disposedin an area where the display panel 100 is not disposed, that is, on thelower surface of the window 200 protruding outward from a side surfaceof the display panel 100. In an exemplary embodiment, the secondwaterproof tape 512 may not overlap the display panel 100 as illustratedin FIG. 6. In other words, an inner side surface 512IS of the secondwaterproof tape 512 may be spaced outward from the second side surface100S2 of the display panel 100 by a predetermined distance. An outerside surface 5120S of the second waterproof tape 512 is located inside asecond side surface 200S2 of the window 200. In other words, the window200 may protrude from the outer side surface 5120S of the secondwaterproof tape 512, so that a portion of the lower surface of thewindow 200 is exposed.

In an embodiment, when the FPCB 110 is disposed on a side of the displaypanel 100, a waterproof tape 510 may not overlap the FPCB 110. That is,as illustrated in FIG. 5, an inner side surface 514IS of the fourthwaterproof tape 514 may be spaced apart from an outermost portion of theFPCB 110 by a predetermined distance.

Thicknesses of the waterproof tapes 511 and 513 attached to the lowersurface of the under-panel sheet 400 may be different from those of thewaterproof tapes 512 and 514 attached to the lower surface of the window200. That is, the second waterproof tape 512 and the fourth waterprooftape 514 attached to the lower surface of the window 200 may be formedthicker than the first waterproof tape 511 and the third waterproof tape513 attached to the lower surface of the lower panel 400 to compensatefor a step difference. In a specific embodiment, the thickness of thesecond waterproof tape 512 may be the same as the sum of the thicknessof the first waterproof tape 511, the thickness of the touch panel 300,the thickness of the display panel 100 and the thickness of theunder-panel sheet 400, as illustrated in FIG. 6. In other words, ashortest distance from the lower surface of the window 200 to a lowersurface of the first waterproof tape 511 may be the same as a shortestdistance from the lower surface of the window 200 to a lower surface ofthe second waterproof tape 512. In this case, the difference between thethicknesses of the waterproof tapes 510 (511 and 512) can compensate fora step difference created by the display panel 100, the touch panel 300and the under-panel sheet 400 disposed between the first waterproof tape511 and the window 200. In addition, the buffering function and/or theheat dissipation function can be provided by the thick waterproof tapes512 and 514 on both short sides SS1 and SS2 of the display device 10where the under-panel sheet 400 is not disposed.

The first waterproof tape 511 and the third waterproof tape 513 disposedalong both long sides LS1 and LS2 of the display device 10 may bearranged adjacent to the second waterproof tape 512 and the fourthwaterproof tape 514 disposed along both short sides SS1 and SS2 of thedisplay device 10 at each corner of the display device 10. Specifically,a short side of the first waterproof tape 511 extending in a lengthwisedirection of the display device and a short side of the third waterprooftape 513 extending in the lengthwise direction of the display device 10may be disposed adjacent to a long side of the second waterproof tape512 extending in a widthwise direction of the display device 10. Inaddition, the other short side of the first waterproof tape 511 and theother short side of the third waterproof tape 513 may be disposedadjacent to a long side of the fourth waterproof tape 514. However, thewaterproof tapes 511 through 514 may not overlap each other, and a spacemay be formed between the waterproof tapes 511 through 514. In aspecific embodiment, since the first waterproof tape 511 can be disposedonly in the second area EA, a short side of the first waterproof tape511 may be disposed adjacent to a region of a long side of the secondwaterproof tape 512 which is disposed in the second area EA.

A waterproof resin 520 may be disposed in each space between thewaterproof tapes 511 through 514. The waterproof resin 520 may fill eachspace between the waterproof tapes 510 to completely block the areainside the waterproof member 500 from the outside. That is, thewaterproof resin 520 may be disposed to prevent the formation of a gapbetween the waterproof tapes 511 through 514. Further, the waterproofresin 520 may be disposed in a space between the side surfaces of thedisplay panel 100, the touch panel 300 and the under-panel sheet 400. Asa result, the waterproof resins 520 may connect the waterproof tapes 511through 514, so that the waterproof member 500 can have a continuousframe shape as a whole. The waterproof member 500 may be coupled to thebracket 600 to completely block the area inside the waterproof member500 from an external material.

In an embodiment, the waterproof tapes 510 may be double-sided tapeshaving a waterproof function. In this case, since no additional adhesiveis required, the display device 10 can be made slimmer. Each of thewaterproof tapes 510 includes a substrate (not illustrated) and abonding layer (not illustrated) disposed on upper and lower surfaces ofthe substrate. The substrate may be made of, but not limited to,polyurethane (PU) or polyethylene terephthalate (PET). The bonding layermay include an adhesive layer, a sticky layer, or a resin layer. Forexample, the bonding layer may contain a polymer material classifiedinto a silicone polymer, a urethane polymer, an SU polymer having asilicone-urethane hybrid structure, an acrylic polymer, an isocyanatepolymer, a polyvinyl alcohol polymer, a gelatin polymer, a vinylpolymer, a latex polymer, a polyester polymer, a water-based polyesterpolymer, or the like.

FIG. 7 is a cross-sectional view of an under-panel sheet 400 accordingto an embodiment. FIG. 8 is a cross-sectional view of an under-panelsheet 401 according to an embodiment. In FIGS. 7 and 8, the specificstacked structure of each of the under-panel sheets 400 and 401 isillustrated.

Referring to FIG. 7, the under-panel sheet 400 may include a firstfunctional layer 411, a second functional layer 412, and a thirdfunctional layer 413 stacked sequentially. In addition, the under-panelsheet 400 may include a first interlayer bonding layer 421 and a secondinterlayer bonding layer 422 which bond the functional layer 411, thesecond function layer 412 and the third functional layer 413 together.

The first functional layer 411 is a functional layer located at anuppermost position, that is, a functional layer disposed closest to thedisplay panel 100. In an embodiment, the first functional layer 411 maybe a buffer member that alleviates external impact. The first functionallayer 411 can prevent the display device 10 from being damaged byabsorbing some of the impact applied to the display panel 100.

The first functional layer 411 may be made of a polymer resin such aspolyurethane, polycarbonate, polypropylene or polyethylene, or may bemade of a sponge formed by foaming a rubber liquid, a urethane materialor an acrylic material.

The first functional layer 411 may have a thickness of about 100 toabout 150 μm. When the thickness of the first functional layer 411 isabout 150 m or less, a sufficient buffering effect can be obtained whilethe display device 10 can be made thinner. When the thickness of thefirst functional layer 411 is about 100 μm or more, the first functionallayer 411 is thick enough to fully absorb external impact. Therefore,the first functional layer 411 can effectively protect the displaydevice 10.

The second functional layer 412 may be disposed under the firstfunctional layer 411. In an embodiment, the second functional layer 412may be a support member that supports the under-panel sheet 400. Inaddition, the second functional layer 412 may be a strength reinforcingmember that reinforces the display device 10 against external impact.That is, the second functional layer 412 assists the first functionallayer 411 to secure the maximum impact resistance of the display device10.

The second functional layer 412 may include a polymer resin such aspolyimide (PI) or polyethylene terephthalate (PET).

In an exemplary embodiment, the second functional layer 412 may be madeof polyimide (PI). Since the polyimide (PI) has excellent heatresistance, even if the display device 10 is exposed to a hightemperature, the second functional layer 412 may hardly contract. Here,the term “high temperature” denotes a high enough temperature to whichpeople can be exposed in their daily lives, for example, a temperatureof 40 degrees or more. When the second functional layer 412 contracts,the under-panel sheet 400 may be distorted and thus detached from thedisplay panel 100. In this case, each function of the under-panel sheet400 may not be sufficiently exhibited. In addition, if the secondfunctional layer 412 contracts, a gap may be formed between thewaterproof member 500 and the second functional layer 412. Therefore,the waterproof performance can be degraded.

A thickness of the second functional layer 412 may be within the rangeof about 25 to 50 μm. That is, a ratio of the thickness of the firstfunctional layer 411 to the thickness of the second functional layer 412may be about 3 to 6 times. Preferably, the ratio of the thickness of thefirst functional layer 411 to the thickness of the second functionallayer 412 may be about 3 to 6 times. The display device 10 including thebent second area EA may be vulnerable to external impact as comparedwith the display devices 20 and 30 composed only of the first area CA.That is, when an impact of the same intensity is applied, a bent portionis subjected to a greater stress than a flat portion. Therefore, thedisplay device 10 including the bent second area EA can be easilydamaged by external impact. When the thickness of the second functionallayer 412 is about 25 μm or more, in other words, when the ratio of thethickness of the first functional layer 411 to the thickness of thesecond functional layer 412 is 3 times or more, not only the first areaCA but also the second area EA can be sufficiently protected. Inaddition, when the ratio of the thickness of the first functional layer411 to the thickness of the second functional layer 412 is 3 times ormore, the second functional layer 412 can withstand the pressuretransmitted from the outside to the display device 10, thereby moreeffectively preventing the display panel 100 from being damaged. Also,the second functional layer 412 can be prevented from contracting due toheat.

When the thickness of the second functional layer 412 is about 50 μm orless, that is, when the ratio of the thickness of the first functionallayer 411 to the thickness of the second functional layer 412 is 6 timesor less, the second functional layer 412 may be elastic enough to bedisposed along the second area EA of the display device 10.

Specifically, the second functional layer 412 can have a high level ofelasticity depending on the characteristics of its constituent material.For example, when the second functional layer 412 is made of polyimide(PI), the elastic modulus of the second functional layer 412 is about330 kg/mm2. Therefore, when the second functional layer 412 is toothick, it may be difficult for the second functional layer 412 to bendwith an appropriate curvature along the curvature of the second area EA.In an exemplary embodiment, the thickness of the first functional layer411 may be about 125 μm, and the thickness of the second functionallayer 412 may be about 25 μm.

The first interlayer bonding layer 421 may be disposed between the firstfunctional layer 411 and the second functional layer 412. That is, thefirst interlayer bonding layer 421 may be interposed between the firstfunctional layer 411 and the second functional layer 412 to bond thefirst functional layer 411 and the second functional layer 412 together.

The first interlayer bonding layer 421 may be an adhesive layercontaining an adhesive or a sticking agent. For example, the firstinterlayer bonding layer 421 may be a pressure sensitive adhesive (PSA),an OCA, or an OCR.

A thickness of the first interlayer bonding layer 421 may be similar tothe thickness of the second functional layer 412. That is, a ratio ofthe thickness of the second functional layer 412 to the thickness of thefirst interlayer bonding layer 421 may be 1 to 2.5 times, preferably, 1to 1.5 times, and, more preferably, 1 to 1.04 times. If the firstinterlayer bonding layer 421 is too thin compared with the secondfunctional layer 412, the first functional layer 411 and the secondfunctional layer 412 may not be sufficiently bonded together. Inaddition, if the first interlayer bonding layer 421 is too thickcompared with the second functional layer 412, the overall thickness ofthe under-panel sheet 400 may increase, making it difficult to make thedisplay device 10 thinner.

Further, the thickness of the first interlayer bonding layer 421 may beabout 20 to about 50 μm, preferably, 25 to 35 μm, and, more preferably,26 μm. If the first interlayer bonding layer 421 is too thick, thethickness of the display device 10 cannot be reduced, and the materialcost is increased. Therefore, the thickness of the first interlayerbonding layer 421 may be 50 mm or less. The first interlayer bondinglayer 421 may have an adhesive strength sufficient to prevent the firstfunctional layer 411 and the second functional layer 412 from beingdetached from each other. That is, the first interlayer bonding layer421 should have an adhesive strength sufficient to maintain the secondfunctional layer 412 having a certain level of elasticity in a bentshape while keeping the second functional layer 412 attached to thefirst functional layer 411. The first interlayer bonding layer 421having a thickness of about 20 μm or more can secure an adhesivestrength sufficient to firmly bond the first functional layer 411 andthe second functional layer 412. The first interlayer bonding layer 421having a thickness of 26 μm can have an adhesive strength sufficient toprevent the first functional layer 411 and the second functional layer412 from being isolated from each other by the elastic force of thesecond functional layer 412 in the second area EA while making thedisplay device 10 thinner.

The third functional layer 413 may be disposed under the secondfunctional layer 412. In an embodiment, the third functional layer 413may be a heat dissipation member. The third functional layer 413 canshield an electromagnetic wave and dissipate the heat generated insidethe display device 10 to the outside. For example, the third functionallayer 413 may be made of a conductive metal having good thermalconductivity such as copper, silver, gold, aluminum, nickel, or acombination of these metals.

The third functional layer 413 may have a thickness of about 9 to 18 μm.When the thickness of the third functional layer 413 is about 9 μm ormore, the third functional layer 413 can rapidly diffuse the heatgenerated inside the display device 10 to suppress a local temperaturerise in the display device 10. When the thickness of the thirdfunctional layer 413 is about 18 μm or less, an increase in themanufacturing cost can be prevented, and the display device 10 can bemade thinner.

The second interlayer bonding layer 422 may be disposed between thesecond functional layer 412 and the third functional layer 413. That is,the second interlayer bonding layer 422 may be interposed between thesecond functional layer 412 and the third functional layer 413 to bondthe second functional layer 412 and the third functional layer 413together.

The second interlayer bonding layer 422 may be made of, but not limitedto, an acrylic adhesive, an epoxy adhesive, a silicone adhesive, or amixture of these materials. In an embodiment, the second interlayerbonding layer 422 may be made of an adhesive containing a thermosettingepoxy material. When the second interlayer bonding layer 422 undergoesheat curing, the strength of the second interlayer bonding layer 422 isincreased. Therefore, the second interlayer bonding layer 422 canprotect the display device 10 more effectively. In an embodiment, thesecond interlayer bonding layer 422 may be made of an acrylic adhesive.Since an acrylic adhesive layer has a heat conduction function, a moreexcellent heat dissipation performance can be secured.

Referring to FIG. 8, a fourth functional layer 4132 may be disposedbetween a second functional layer 412_1 and a third functional layer413_1 of the under-panel sheet 401.

The fourth functional layer 4132 may include thermally conductiveparticles. The thermally conductive particles may be particles having athermal conductivity of 1 W/mK or more. Examples of the thermallyconductive particles include carbon black, carbon nanotubes, carbonnanofibers, and graphenes. The fourth functional layer 4132 may includea single type of thermally conductive particles or a mixture of two ormore types of thermally conductive particles. In this case, the thirdfunctional layer 413_1 can function to fix the thermally conductiveparticles.

The above thermally conductive particles may have a plate-like structurein which carbon atoms are connected in a horizontal direction. In thiscase, the fourth functional layer 4132 may have a higher thermalconductivity in the horizontal direction than in a vertical directionand may have an excellent heat dissipation effect. In addition, sincethe fourth functional layer 413_2 can have a good elastic modulus, itmay be disposed only in the first area CA and not in the second area EA.

The fourth functional layer 413_2 may have a thickness of about 15 to 25μm, preferably, 17 μm. When the thickness of the fourth functional layer413_2 is about 15 μm or more, a sufficient heat dissipation effect inthe vertical direction can be obtained. When the thickness of the fourthfunctional layer 413_2 is less than about 25 μm, the display device 10can be made thinner.

In the above embodiments, a case where the first functional layers 411and 41_1 are buffer members, the second functional layers 412 and 412_1are strength reinforcing members, the third functional layers 413 and413_1 and the fourth functional layer 414 and 414_1 are heat dissipationmembers has been described. Here, the stacking order can beappropriately changed within a range that does not impair the objectivesof the inventive concept. For example, the first functional layers 411and 41_1 may be strength reinforcing members, the second functionallayers 412 and 412_1 may be buffer members, and the third functionallayers 413 and 413_1 and the fourth functional layer 414 and 414_1 maybe heat dissipation members.

Hereinafter, other embodiments of the inventive concept will bedescribed.

FIG. 9 is an exploded perspective view of a display device 20 accordingto an embodiment. FIG. 10 is a rear view of the display device 20according to the embodiment of FIG. 9. FIGS. 9 and 10 show that anunder-panel sheet 2400 and a waterproof member 2500 can also be appliedto the flat display device 20. In the following embodiment, adescription of components identical to those of the above-describedembodiment will be omitted or given briefly, and differences from theabove-described embodiment will be mainly described.

Referring to FIGS. 9 and 10, the display device 20 may be composed onlyof a first area CA. That is, the display device 20 may be a flat displaydevice that is formed generally flat without a bent area.

The waterproof member 2500 of the display device 20 may not overlap theunder-panel sheet 2400 and may be disposed on a lower surface of awindow 2200. That is, a first waterproof tape 2511 and a thirdwaterproof tape 2513 disposed on both long sides LS1 and LS2 of thedisplay device 20 may not overlap the under-panel sheet 2400 and may bedisposed directly on the lower surface of the window 2200. In otherwords, the waterproof member 2500 may be disposed on an exposed portionof the lower surface of the window 2200 which protrudes outward fromside surfaces of the display panel 2100. However, the inventive conceptis not limited to this case, and the first waterproof tape 2511 and thethird waterproof tape 2513 can also overlap the under-panel sheet 2400to be disposed directly on a lower surface of the under-panel sheet2400, like the first waterproof tape 511 and the third waterproof tape513 of the display device 10 according to the embodiment of FIG. 1.

FIG. 11 is a cross-sectional view taken along the line XI-XI′ of FIG.10.

Referring to FIGS. 10 and 11, a side surface 2100S1 of the display panel2100, a side surface 2300S1 of a touch panel 2300, and a side surface2400S1 of the under-panel sheet 2400 may be substantially aligned witheach other.

An inner side surface of the waterproof tape 2510 (2511 and 2513) may bespaced outward from the side surface 2400S1 of the under-panel sheet2400 by a predetermined distance. That is, as illustrated in FIG. 11, aninner side surface 2511IS of the first waterproof tape 2511 may belocated outside the side surface 2400S of the under-panel sheet 2400.

FIG. 12 is a cross-sectional view taken along the line XII-XII′ of FIG.10.

Referring to FIGS. 10 and 12, the waterproof tapes 2511 through 2514 mayhave the same thickness. That is, since all of the waterproof tapes 2511through 2514 are disposed on the lower surface of the window 2200, nostep is formed between them.

Therefore, the waterproof tapes 2511 through 2514 can have the samethickness.

The waterproof tapes 2511 through 2514 may be separated from each otherby a predetermined distance at each corner of the display device 20.That is, the first waterproof tape 2511, the second waterproof tape2512, the third waterproof tape 2513, and the fourth waterproof tape2514 may be disposed adjacent to each other but may not overlap eachother.

A waterproof resin 2520 may be disposed in each space between thewaterproof tapes 2511 through 2514.

In an embodiment, as illustrated in FIG. 12, the waterproof resin 2520may be disposed in a space between a short side of the first waterprooftape 2511 and a long side of the second waterproof tape 2512.

Although not illustrated in the drawings, in an embodiment, a space maybe formed between a long side of the first waterproof tape 2511 and ashort side of the second waterproof tape 2512. That is, while a space isformed in the widthwise direction of the display device 20 in FIGS. 10and 12, it can also be formed in the lengthwise direction of the displaydevice 20 in an embodiment. In this case, the waterproof resin 2520 maybe disposed in each space formed in the lengthwise direction of thedisplay device 20.

In the current embodiment, the inside of the display device 20 may becompletely blocked from the outside by the waterproof member 2500 and abracket 2600 coupled to the waterproof member 2500. That is, since thereis no space between the waterproof member 2500 and the bracket 2600, itmay be difficult for a liquid outside the display device 20 to penetrateinto the display device 20.

FIG. 13 is a rear view of a display device 30 according to anembodiment.

Referring to FIG. 13, a waterproof member 3500 of the display device 30may be shaped like a continuous line extending along the outer peripheryof a window 3200. That is, the waterproof member 3500 may be formed onlyof a waterproof tape and shaped like a quadrilateral frame. In thiscase, since a space formed between a plurality of waterproof tapes isnon-existent, a waterproof resin can be omitted.

The waterproof member 3500 may have the same thickness throughout thedisplay device 30. That is, like the waterproof member 2500 of thedisplay device 20, the waterproof member 3500 of the display device 30does not overlap an under-panel sheet 3400 and is disposed on a lowersurface of the window 3200. Therefore, no step may be formed betweenareas of the waterproof member 3500.

The display device 30 according to the current embodiment can protectinternal components of the display device 30 from an external liquidsuch as moisture by using only the waterproof tape 3500. That is, theomission of the waterproof resin can simplify the process and reduce thecost.

A display device according to an embodiment includes an under-panelsheet having a strength reinforcing member, and the under-panel sheetprevents the display device from being damaged by external impact.

In addition, since the introduction of a liquid such as moisture intothe display device is prevented, a waterproof function of the displaydevice can be improved.

However, the effects of the inventive concept are not restricted to theone set forth herein. The above and other effects of the inventiveconcept will become more apparent to one of daily skill in the art towhich the inventive concept pertains by referencing the claims.

While the inventive concept has been particularly illustrated anddescribed with reference to exemplary embodiments thereof, it will beunderstood by those of ordinary skill in the art that various changes inform and detail may be made therein without departing from the spiritand scope of the inventive concept as defined by the following claims.The exemplary embodiments should be considered in a descriptive senseonly and not for purposes of limitation.

What is claimed is:
 1. A display device comprising: a display panelwhich comprises a first side extending in a first direction, a secondside extending in a second direction intersecting the first direction, athird side opposite to the first side, and fourth side opposite to thesecond side; a window which is disposed on the display panel andcomprises a first area overlapping the display panel and a second areaprotruding outward from the display panel; a bracket disposed under thedisplay panel; and a waterproof tape disposed between the window and thebracket, wherein the waterproof tape comprises: a first waterproofportion disposed along the first side of the display panel, a secondwaterproof portion disposed along the second side of the display panel,a third waterproof portion disposed along the third side of the displaypanel, and a fourth waterproof portion disposed along the fourth side ofthe display panel, and wherein the first waterproof portion overlaps thedisplay panel, and the second waterproof portion overlaps the secondarea of the window.
 2. The display device of claim 1, furthercomprising: a first waterproof resin disposed in a space between thefirst waterproof portion and the second waterproof portion.
 3. Thedisplay device of claim 3, wherein the first waterproof resin overlapsthe second area of the window.
 4. The display device of claim 1, whereinthe third waterproof portion overlaps the display panel, and wherein thefourth waterproof portion overlaps the second area of the window.
 5. Thedisplay device of claim 4, further comprising: a first waterproof resindisposed in a space between the first waterproof portion and the secondwaterproof portion; and a second waterproof resin disposed in a spacebetween the third waterproof portion and the second waterproof portion.6. The display device of claim 5, wherein the first waterproof resin andthe second waterproof resin overlap the second area of the window. 7.The display device of claim 1, wherein the first waterproof portion isdisposed between the display panel and the bracket, and wherein thesecond waterproof portion does not overlap the display panel.
 8. Thedisplay device of claim 1, further comprising: a flexible circuit boarddisposed at the second side of the display panel, wherein the secondwaterproof tape does not overlap the flexible circuit board.
 9. Thedisplay device of claim 1, further comprising: an under-panel sheetdisposed between the display panel and the bracket, wherein the firstwaterproof portion and the third waterproof portion are disposed betweenthe under-panel sheet and the bracket, and wherein the second waterproofportion and the fourth waterproof portion do not overlap the under-panelsheet.
 10. The display device of claim 9, wherein the first waterproofportion and the third waterproof portion directly contact theunder-panel sheet and the bracket, and wherein the second waterproofportion and the fourth waterproof portion directly contact the bracketand the window.
 11. The display device of claim 9, wherein theunder-panel sheet comprises a buffer member and a strength reinforcingmember.
 12. The display device of claim 11, wherein the strengthreinforcing member comprises polyimide (PI).
 13. The display device ofclaim 1, wherein the fourth waterproof portion is extended from thefirst waterproof portion in the second direction, and wherein the thirdwaterproof portion is extended from the fourth waterproof portion in thefirst direction.
 14. The display device of claim 1, wherein a length ofthe first side of the display panel in the first direction is longerthan a length of the second side of the display panel in the seconddirection.